1. Field of the Invention
This invention relates to an improved dental articulator and more particularly to a device for recording and reproducing mandibular motion.
2. Background of the Invention
Geometric details describing the relative locations of the teeth, the areas and inclinations of their individual surfaces, and the positions of the surfaces making contact during "full" occlusion, relative to the hinging joint of the jaw, each affect the health of the teeth and of the hinge of the jaw, i.e., the "temporo-mandibular joint." These details are altered by growth, wear, disease, trauma, surgery, orthodontic treatment, treatment of caries, and by addition of fixed prosthodontic devices. Also, these details are totally changed by introduction of full dentures. In diagnosing and treating functional disorders arising from misalignment of the teeth or the hinging joint, or in guiding treatment of normal patients to avoid introducing functional disorders, dentists use a two-part technique.
First the positions of the maxillary and mandibular teeth relative to the cranially fixed sockets for the temporo-mandibular joints are recorded by making an impression of those teeth and by relating the impression to the socket through mechanical means attached to the impression and extending extra-orally to a position in proximity to the socket and joint; these mechanical means have markers and adjustments which allow those markers to be positioned so as to minimize translation during hinging maneuvers of the jaw.
Second, the mechanical means and the impression attached thereto are mounted on an articulator, which is a device providing means for simulating motions of the temporo-mandibular joint. The mechanical means and impression are used to locate casts of the patient's teeth in the same relative position to the hinge axis of the articulator as the actual teeth had to the hinge axis of the patient's temporo-mandibular joint. Motions and interactions of the casts of the patient's upper and lower teeth are then studied and altered by the dentist to optimize treatment.
Articulators offering varying degrees of simulation are well known but with all of these prior art devices, as the simulation becomes more complex to allow greater adjustability, the devices have a higher initial cost and require more time by the clinician to effect the adjustments. Moreover, since the basic articulator is used for a number of patients, it must be readjusted for each new simulation. In most prior art articulators, however, no effective way is provided by means of dials, indicators, or the like, for keeping a record of the adjustments necessary for a particular patient which is adequate to allow repeated mounting of the casts or transfer of the casts to an alternate articular or device without either requiring significant time for readjustment or without losing significant precision of alignment.